Indonesia July and August are not difficult months for a warm-weather trip, but choosing the right region matters. Indonesia is one of the strongest all-round options: Bali Nusa Dua averages 28°C (82°F) with 51 mm (2 in) of rain in July and 27°C (81°F) with just 40 mm (1.6 in) in August. Zanzibar is similarly reliable, with 38 mm (1.5 in) in July and 37 mm (1.5 in) in August. Thailand can work well if you choose Koh Samui rather than the wetter Phuket side. Mexico is more mixed: Cancún is hot and sunny but wetter, while Cabo San Lucas is substantially drier. Sri Lanka's east coast is another interesting alternative, although temperatures around Trincomalee are very hot at 34°C (93°F).
July and August weather: the quick comparison
The table below compares representative holiday destinations using historical averages from Weather & Climate. It deliberately compares specific destinations rather than entire countries, because summer weather can differ dramatically from one coast to another.
| Destination | July daytime | July rainfall | August daytime | August rainfall | Best for |
|---|---|---|---|---|---|
| Bali Nusa Dua, Indonesia | 28°C (82°F) | 51 mm (2 in) | 27°C (81°F) | 40 mm (1.6 in) | Dry, sunny beach weather |
| Chaweng Beach, Koh Samui | 30°C (86°F) | 98 mm (3.9 in) | 30°C (86°F) | 107 mm (4.2 in) | Thailand in European summer |
| Cancún, Mexico | 31°C (88°F) | 90 mm (3.5 in) | 31°C (88°F) | 116 mm (4.6 in) | Hot Caribbean beaches |
| Cabo San Lucas, Mexico | 33°C (91°F) | 17 mm (0.7 in) | 33°C (91°F) | 61 mm (2.4 in) | Drier Mexican weather |
| Zanzibar City, Tanzania | 28°C (82°F) | 38 mm (1.5 in) | 28°C (82°F) | 37 mm (1.5 in) | Warm, reliably dry tropics |
| Trincomalee, Sri Lanka | 34°C (93°F) | 30 mm (1.2 in) | 34°C (93°F) | 44 mm (1.7 in) | Hot east-coast beach weather |
Historical averages from Weather & Climate. Conditions in individual years will vary.
Indonesia: probably the safest all-round choice
For travelers who want tropical warmth, beaches and relatively dependable dry weather, Indonesia is difficult to beat in July and August. Bali Nusa Dua in July averages 28°C (82°F) during the day and 25°C (77°F) at night, with 51 mm (2 in) of rain over only about two days. Sunshine reaches 248 hours and the sea averages 27°C (81°F).
August is even drier. Nusa Dua averages 27°C (81°F) during the day, 25°C (77°F) at night and 40 mm (1.6 in) of rainfall over around one day. Sunshine increases to about 261 hours, while the sea remains comfortable at 26°C (79°F).
Bali is not the only strong Indonesian option. Kuta Lombok is even drier in late summer. Weather & Climate records 30°C (86°F) days and 27 mm (1.1 in) of rain in July, followed by 29°C (84°F) days and only 17 mm (0.7 in) in August. August also brings around 257 sunshine hours.
That makes Indonesia especially attractive for a trip combining beaches with sightseeing. Bali offers the widest range of accommodation and cultural stops, while Lombok can be the better choice if minimal rainfall is the main priority.
Thailand: choose Koh Samui, not Thailand in general
Thailand is a good example of why national weather advice can be misleading. In July and August, the Gulf of Thailand around Koh Samui performs considerably better than the Andaman coast around Phuket.
Chaweng Beach on Koh Samui averages 30°C (86°F) during the day and 27°C (81°F) at night in both months. Rainfall is 98 mm (3.9 in) in July and 107 mm (4.2 in) in August, with around 156 and 152 sunshine hours respectively. There are showers, but these figures are manageable for many beach holidays.
Phuket is a very different story. In July it averages 30°C (86°F) during the day, 27°C (81°F) at night and 243 mm (9.6 in) of rain over around 20 days. August is even wetter at 265 mm (10 in), again across roughly 20 rainy days. Sunshine is around 152 hours in July and 150 hours in August.
So if Thailand is the dream, summer does not automatically rule it out. It simply makes island selection much more important. Koh Samui, Lamai and nearby Gulf islands are more sensible weather choices than Phuket if rainfall is high on your list of concerns.
Mexico: hot everywhere, but the coast you choose matters
Mexico can work in July and August, but it is not as consistently dry as Indonesia or Zanzibar. Cancún in July averages 31°C (88°F) during the day and 27°C (81°F) at night, with 90 mm (3.5 in) of rain over around 12 days. Sunshine is still strong at about 233 hours, and the Caribbean Sea averages a very warm 29°C (84°F).
August keeps the same 31°C (88°F) daytime and 27°C (81°F) nighttime averages, but rainfall rises to 116 mm (4.6 in) over around 13 days. Sunshine remains around 233 hours and the sea is again 29°C (84°F). In other words, Cancún can still deliver hot beach weather, but you should expect tropical showers as part of the trip.
If you want Mexico but would rather reduce the chance of rain, look west. Cabo San Lucas averages 33°C (91°F) in July with just 17 mm (0.7 in) of rainfall. August remains 33°C (91°F), although rainfall increases to 61 mm (2.4 in). This is much drier than Cancún, but also extremely hot. |
One important drawback in July and August is sargassum. Cancun and the wider Mexican Caribbean can receive large amounts of floating seaweed during summer. Mexico’s Navy identifies roughly April to October as the main sargassum-arrival cycle in Quintana Roo, so July and August sit right inside that period. Conditions vary a lot from beach to beach and even from one day to the next, but heavy accumulations can make swimming less appealing and, once the seaweed decomposes onshore, it can produce a strong unpleasant smell. Local authorities and hotels actively remove it, but it is still something worth checking shortly before you travel.
So Mexico requires a more specific decision than Bali. Choose Cancún for the warm Caribbean and easy beach holiday, accepting more rain. Choose Baja California Sur if dry weather matters more and you are comfortable with stronger heat.
Zanzibar: one of the most reliable tropical alternatives
Zanzibar deserves to be in the same conversation as Bali for July and August. Zanzibar City averages 28°C (82°F) during the day and 23°C (73°F) at night in July, with only 38 mm (1.5 in) of rainfall over around seven days. August is almost identical at 28°C (82°F), 23°C (73°F) and 37 mm (1.5 in) of rain.
That stability is a major advantage. You do not have the large month-to-month increase seen in parts of Mexico, and rainfall is far lower than on Thailand's Phuket coast.
There is some variation around the island. In August, for example, Jambiani averages 34 mm (1.3 in), Paje 33 mm (1.3 in) and Nungwi 46 mm (1.8 in). The differences are relatively modest, so travelers can choose a coast primarily on the experience they want rather than chasing a dramatically drier microclimate.
Zanzibar is particularly compelling for travelers who want warm beach weather without the intense 33°C (91°F) to 34°C (93°F) afternoons found in Cabo or eastern Sri Lanka.
Sri Lanka: the east coast is the summer option
Sri Lanka is another country where the correct coast makes all the difference. Around Trincomalee in the east, July is relatively dry despite being hot. Daytime temperatures average 34°C (93°F), nights 27°C (81°F), rainfall 30 mm (1.2 in) and sunshine about 226 hours.
August stays at 34°C (93°F) during the day and 27°C (81°F) at night. Rainfall increases only modestly to 44 mm (1.7 in), while sunshine actually rises to around 254 hours. Nearby Nilaveli and Uppuveli show a very similar pattern.
The main reservation is heat. 34°C (93°F) afternoons combined with 27°C (81°F) nights are considerably warmer than Bali or Zanzibar. For travelers who love hot tropical weather, the east coast can be excellent. For long sightseeing days, Indonesia's milder 27°C (81°F) to 28°C (82°F) averages may be easier.
So which destination is best in July?
For the most balanced July weather, Indonesia and Zanzibar stand out. Bali Nusa Dua offers 28°C (82°F) days, 51 mm (2 in) of rain, 248 sunshine hours and a 27°C (81°F) sea. Kuta Lombok is even drier at 27 mm (1.1 in). Zanzibar City is slightly cooler at 28°C (82°F) and receives only 38 mm (1.5 in).
Koh Samui is a workable Thailand option, but its 98 mm (3.9 in) rainfall total is clearly higher. Cancún is similarly warm and sunny, with 90 mm (3.5 in), while Cabo is much drier at 17 mm (0.7 in) but hotter at 33°C (91°F). Trincomalee is also dry at 30 mm (1.2 in), although its 34°C (93°F) average daytime temperature can be demanding.
And which destination is best in August?
August strengthens Indonesia's case. Bali Nusa Dua drops to 40 mm (1.6 in) of rain and reaches about 261 sunshine hours, while Kuta Lombok receives only 17 mm (0.7 in). Zanzibar remains remarkably stable at 37 mm (1.5 in).
Koh Samui is still possible at 107 mm (4.2 in), but Phuket becomes a much wetter choice at 265 mm (10 in). Cancún rises to 116 mm (4.6 in), while Cabo remains considerably drier at 61 mm (2.4 in). Trincomalee stays dry at 44 mm (1.7 in) but remains very hot.
The short answer: where should you go?
- For the best all-round July and August weather: Bali or Lombok. Warm, sunny and relatively dry in both months.
- For a tropical alternative with very stable weather: Zanzibar, with around 37 mm (1.5 in) to 38 mm (1.5 in) of rain.
- For Thailand: Koh Samui is the more sensible summer choice. Phuket is much wetter.
- For Mexico: Cancún works if you accept showers; Cabo is much drier but hotter.
- For Sri Lanka: choose the east coast around Trincomalee, especially if strong heat is not a problem.
Our weather-first pick
If weather is the main deciding factor, Indonesia has the strongest overall case for both July and August. Bali combines moderate tropical temperatures, abundant sunshine, warm sea water and relatively little rain, while Lombok is even drier. Zanzibar is the closest alternative if you want Africa rather than Asia.
Thailand and Mexico can both be excellent, but they require more careful regional choices. Koh Samui performs much better than Phuket in these months, while Baja California Sur is drier than the Mexican Caribbean. Sri Lanka's east coast is another strong option, but its 34°C (93°F) daytime heat makes it a more specific choice. In July and August, the right coast matters at least as much as the right country.